When using many electronic test and measurement equipment products, such as, oscilloscopes, logic analyzers, communication systems protocol analyzers, spectrum analyzers, and the like, to troubleshoot a circuit under test, it is quite common to employ a circuit card extender to elevate a particular circuit card and thereby facilitate connection of test probes to the circuit under test (sometimes referred to as a System Under Test, or SUT). In the distant prior art, this feature was implemented by providing a board with a card edge connector on one end, a card edge receptacle on the other end, and a plurality of printed traces running straight across the board from the card edge to the receptacle. Probing was performed directly on the circuit board under test.
A probing adapter is nonintrusive hardware that allows a logic analyzer to acquire data from a bus in its own operating environment with little, if any, effect on the target system. A probing adapter comprises a circuit board and a socket for a circuit card to be tested. A probing adapter plugs into a bus receptacle on the target system and signals from the system bus flow through the probing adapter to a logic analyzer. Modern probing adapters must support logic analyzers which have the capability of monitoring a large number of channels (for example 136 channels), simultaneously. Consequently, in addition to elevating the circuit under test from its motherboard, by interposing between the circuit under test and its normal connector on the motherboard, a probing adapter also provides connection points (i.e., sockets) for high density multiconductor probes.
Unfortunately, prior art probing adapters suffered from several disadvantages. Among these disadvantages are: signal reflections caused by impedance mismatches due to the use of the connectors to turn the probe adapter from a vertical orientation to a horizontal orientation for use, and blocking of adjacent slots due to the horizontal orientation of the probing adapter. A probe adapter exhibiting these disadvantages is the FSAGP 32TE AGP Probe manufactured for Hewlett Packard Inc. by FuturePlus Systems Corporation, Colorado Springs, Colo.
What is needed is a probing adapter which does not block adjacent slots and which does not introduce impedance mismatches which would otherwise cause reflective events.